Variable permeability liquid crystalline membranes

Abstract

The instant invention is directed to a variable permeability liquid crystalline membrane, comprising a porous structure containing a polymeric liquid crystal which can undergo a phase change. The instant invention is also directed to a process for regulating the flow of solutes or permeants through a liquid crystalline membrane, comprising changing the phase of a polymeric liquid crystal supported by a porous structure.

What is claimed is: 
     
       1. A variable permeability liquid crystalline membrane, comprising a porous structure containing a polymeric liquid crystal which can undergo a phase change. 
     
     
       2. The membrane of claim 1, wherein said porous substrate is a cellulose ester microporous membrane. 
     
     
       3. The membrane of claim 2, wherein said liquid crystal is poly-γ-benzyl-L-glutamate. 
     
     
       4. The membrane of claim 3, wherein 15 to 23%, by weight, of poly-γ-benzyl-L-glutamate and 77 to 85%, by weight, of solvent is used. 
     
     
       5. A process for regulating the diffusion of solutes or permeants through a liquid crystalline membrane, comprising changing the phase of a polymeric liquid crystal supported by a porous structure. 
     
     
       6. The process of claim 5, wherein the phase of said polymeric liquid crystal is changed by subjecting said crystal to an electric field of 300 to 500 volts per centimeter. 
     
     
       7. The process of claim 5, wherein said porous substrate is a cellulose ester microporous filter. 
     
     
       8. The process of claim 7, wherein said cellulose ester is poly-γ-benzyl-L-glutamate. 
     
     
       9. The process of claim 8, wherein 15 to 23%, by weight, of poly-γ-benzyl-L-glutamate and 77 to 85%, by weight, of solvent is used.